Two problems related to manifold/header/muffler/tail pipe have been reported for the 2012 Jeep Wrangler. The most recently reported issues are listed below.
The heat shield between the muffler and gas tank has worn out where the nuts that secure it to gas tank contact the shield. The shield has clearly deteriorated due to normal driving vibration as there are no moving parts and the shield is not reinforced where the nuts contact it. I've had to add large fender washers to cover the worn thru portion of the shield but this will not be a long term solution as the plate will simply wear out where the new washers contact it.
Noticed a very prominent ticking noise coming from the drivers side of engine. Occurs at idle and gets more pronounced when increasing speed while in park. Notified the dealer and Jeep spent three days at dealership. The service advisor who had 23 years of experience told me when he heard it that it definitely was a lifter problem. So I called Chrysler corp and received a claim number. To make a long story short, I was told that all the pentastar engines made a loud ticking noise from the drivers side and this was a normal variant. Was told that it was in the design of the left exhaust manifold and they all made this noise. After much talking between Chrysler corp and the dealership I was told to come and pick up my Jeep, nothing would be done. I have a friend who is a Dodge mechanic and was told that the pentastar engines are having multiple problems with the left head and cam phaser are going out. . . I am concerned that the engine will catch fire or stall out on the freeway.